Shot pattern control device for shot guns



Jan. 26, 1960 F. A. PACHMAYR ET AL 2,922,242

' SHOT PATTERN CONTROL DEVICE FOR SHOT GUNS Filed April 28, 1958 FRANK A. PACHMA rR LLOYD L. Hus/(Er INV EN I OR.

Bywg

SHOT PATTERN CONTROL DEVICE FOR SHOT GUNS Application April 28, 1958, Serial No. 731,482

6 Claims. (Cl. 4279) This invention has to do generally with muzzle devices for shot guns, and is directed particularly to improvements in the so-called variable choke type of device usable to control the shot pattern by reason of the variability of the nature and degree of direction given the shot in passing through the device.

Heretofore variable choke muzzle devices have been made in the general manner of a body attachable to the gun barrel and containing a tapered bore choke tube. fixed or connected at one end to the barrel and capable of radial variation by expansion or contraction of its opposite end. In such devices, the choke tube has constituted in effect an integral part of the body, and its capacity for shot pattern control has been limited to that degree possible by expansion or contraction of a portion of the tube, as distinguished from its full length.

The present invention departs from such conventional devices in a number of important respects contributing to the attainment of better shot patterns and pattern control, while providing for effective recoil reduction, gas. venting and clean-out, all in a manner affording the further practical advantages of greater simplicity and economy in construction.

One of our major objects is to provide an improved muzzle device characterized by 'the use of a radially variable choke tube prefabricated as a unit independently of the tubular body of the device, and accommodated therein so as to be readily insertible and removable for inspection, replacement or repair. In accomplishing this object we provide a choke tube which by reason of the support given it in the body, may be. made. relatively thin and inexpensively, and rendered accurately responsive to radial variability.

A further feature and object is to render this removable tube radially expansible. and contractible throughout its length so as to control not only the angularity of the shot deflection, but also the minimum bore diameter of.

the tube. In this connection the invention contemplates the desirability of forming the tube with a rear forwardly tapering bore length, and a continuing forward length having substantially uniform diameter. The stated full length, radial variability of. the tube preferably is accomplished by slotting it alternately from both ends, the slots being in a circularly overlapping and spaced relation giving a full length variability that may be exercised while maintaining constant the angular relationship between the entering and exit extents of the tube bore.

Variation of the tube preferably is accomplished by forming the body with a. pair of threadedly connected sections so associatedwith the. tube that relative rotation and consequent relative axial movement of thesections effects, wedge controlling expansion or contraction of both end and. intermediatev portions of the tube. In the interests of giving the tube, particularly when made relatively thin, additional controlled support, the tube may be formed with an external wedge shoulder engageable by a complementary internal body shoulder to conform with the support and variation given the tube at its ends.

atent The invention has further objects and novel features in the form and arrangement of the body sections in relation to the variable tube. The latter preferably is entirely contained within a forward section of the body, screwed to a rear section which is vented for gas escape. Further advantage may be taken of the rear section toward recoil reduction, by providing it with a bore tapering forwardly, and preferably in steps, to the entryof the variable tube, and forming in the wall of the section anarrangement of openings so positioned that the periphery of the gas stream is progressively baflled out through the openings to a degree creative of substantial recoil. re-' duction.

Another object of the invention is to render the device self-cleaning of dirt and wad residue from about the tube, by providing apertures so positioned externally in relation to the forward end'of the tube that the dirt will be displaced by the gun blast in the direction of its forward release.

All the above mentioned features and objects of the. invention, as well as the details of an illustrative embodiment, will be further understood from the following detailed description of the accompanying drawing, in which:

Fig. l is a view showing in side elevation the muzzle device attached to a gun barrel; 7

Fig. 2 is a longitudinal cross-section of the muzzle device as viewed in the plane of line 22 of Fig. 3;

F Fig. 3 is an end view of the right hand portion of Fig. 4 is an end view taken from line 4-4 of Fig. 2;,

Fig. 5 is a fragmentary cross-section on line 5-5 of Fig. 3; and

Fig. 6 is an exploded perspective showing of the muzzle device parts.

Referring first to Fig. 1, the muzzle. device, generally indicated at 10, is shown to be attached to the muzzle end' of typically a 12 gauge shot gun barrel 11 by an appropriate adaptor 12 comprising typically a sleeve 13 fixedto the barrel and externally threaded to receive an adjustable ring 14 and the muzzle device. The latter is shown to comprise a forward tubular section 15 and a rear section 16 internally threaded at 17 to be screwed onto the adaptor sleeve 13.

Section 16 of the muzzle device is shown to havea. forward reduced diameter end portion 18 which has a. threaded connection at 19 with the forward section 15- in a manner permitting rotation and resultant relative axial movement of section 15 and for the purposes later described. The end outer surface 20 of section 16 be.- yond the threads at 19 contains notches 21 at equal circularly spaced intervals, to provide for the detentingaction of a split resilient ring 22 received within anexternal annular groove 23 in section 15, and having. an inturned end 24 extending through opening 25 to coactwithrecesses 21 by detenting action to register different rota: tional positions of section 1'5 relative to the. stationary section 16. The rear surface of section 15' may carrysuitable circularly spaced markings 26 by which the, rotational adjustment may be indexed as with reference. to. thesi'ght 27.

Section 16 has a circular cross-section bore 28 formed.- beyond the threaded'counterbore 29' at a step taper pref-- era'bly' continuing to the end of the section at 30 at a. general angularity typically of about three to five degrees. Gases released by the muzzle blast are partially intercepted and vented from the cage section 16 through slots 31 spaced. both circularly and axially of the: cage As best illustrated in Fig. 2, by reason of the stepped taper given the bore 28, the slot formation presents edges 32 and the steps shoulders 321 which are progressively offset inwardly and in accordance with the angula'rity of the taper, to intercept and deflect outwardly through the slots, peripheral portions of the gas emission, the effect being in addition to venting of some of the gases, to present a progression of baffle edges which receive and transmit to the gun through the muzzle device, a substantial-percentage of the force of the blast to proportionately reduce the recoil effect.

The invention is primarily concerned with our improved shot pattern control means contained within the forward section 15 and adjustable to permit variation of the shot pattern. Such control is effected by a tubular collet 34 characterized by its removability from the body of the muzzle device, and by its capacity for radial contraction or enlargement throughout its length. The tube 34, which may be formed as a single piece turning or machined part of lightweight metal such as aluminum or an aluminum alloy (of which the body sections15 and 16 also may be formed), is made to have a forwardly taperedbore extending throughout a portion or the full' length of the tube. Preferably, we form the bore to have a rear forwardly tapering extent 35 continuing about two-thirds the length 'of the tube, beyond which the exit bore length 36lhas substantially uniform diameter- At this point it may be mentioned that the tapered bore extent 35 serves to deflect the shot accordirlg to the radial constriction or expansion of the tube, and the straight bore extent 36 to project the shot so affected, without disturbing the desired pattern. The tube 34 is rendered radially contractible and expansible throughout its length. by being alternately slotted from both ends. Thus, slots 37 extending the greater portion of the sleeve length and cut from and through its rear end, are alternated by slots 38 similarly cut from and through the. front end, the slots in each case being discontinuous and in circularly overlapping arrangement at uniform angular intervals.

The tube'34 is formed at its end with angular wedge surfaces 39 and 40, and has a forward reduced diameter length 34a beyond an intermediate angular wedge shoulder 41. The end wedge face 40 is engageable by a wedge.

face 42 formed at corresponding angularity on the end of section 16, and the opposite end face 39 of the tube is engaged against an internal angular wedge shoulder 44 within section 15. The latter has larger and smaller:

bore lengths 45 and 46 at opposite sides of shoulder 47 engaging and formed at an angularity corresponding to the tube wedge shoulder 41. The diameters of bores 45 and 46 may correspond substantially with the diameters of the lengths of tube 34 which they receive. As will be apparent, the shot pattern control tube 34 is radially and axially supported both at its ends by engagement against shoulders 42 and 44, and also at an intermediate location by the interengagement of shoulders 41 and 4 7. I

In the interests of rendering the forward section of the muzzle device self-cleaning by the gun blast, of dirt and wad particles tending to collect within slots 37 and 38 and at the outside of the tube, the body section 15 is formed with a circular arrangement of longitudinalvent grooves 48 extending continuously and openly from the'front end of the section through the shoulder 47, as best illustrated in Fig. 2. The force of the gun blast drives some of the gases out through the slots to the outside of the tube, from whence such gases project forwardly through the grooves 48 to carry with them dirt and fiber particles removed from the slots and exterior of the tube. a i

In use, the muzzle device may be employed to pro feet the shot at variable patterns, by virtue of the capacity of the tube 34 for radial variability throughout its length, effected by rotational adjustment of section tion 16. The effect of rotation of section in one direction is to wedge shoulders 42, 47 and 44 respectively against the tube shoulders 40, 41 and 39, with consequent radial contraction of the tube; a corresponding radial release and enlargementresulting from rotational adjustment of the section 15 in .an opposite direction. Whatever may be the direction or extent of adjustment, the relationship between the tube bores 35 and 36 remains the same in that since the angularitiesof the wedge surfaces arersuch as to constrict the tube uniformly throughout its length, the bore extent 35 retains its forward taper .and' the extent 36 remains substantially straight or uniform in diameter.

We claim: 4 A

1. A shot gun muzzle device comprising a tubular body attachable to a gun, said body including forward and rearwardly threadedly interconnected sections, a shot pattern control tube within the body forward section and rearwardly removable therefrom when the sections are relatively disconnected, 'said tube being radially deformable throughout its length and having a bore the rear extent of which tapers forwardly and the forward extent of which has uniform diameter, said tube having an external forwardlyrtapering intermediate shoulder opposite substantially the start of the uniform diameter eX-.

tent of the tube bore, first wedge means on said rearward section and engageable against the rearward end of the tube within said forward section and other wedge means on the forward sectionand engageable against the forward end of the tube and against said intermediate shoulder thereof, said tube forward and rearward ends being tapered to cooperate with said wedge means, said. sections being relatively rotatable to vary uniformly the radial constriction of said tube throughout its entire length and throughout said relative rotation acting to vary said tube constriction by force transmission through said wedge means to the tube.

2. The invention as defined in claim 1 in which said first wedge means and the rearward end of the tube taper rearwardly and said other wedge means and the forward end .ofthe tube taper forwardly.

3. The invention as defined in claim 1 in which said body forward section has a bore receiving the uniform bore diameter extent of said tube, said forward section also having a counterbore receiving the tapered bore extent of the tube.

4. The invention as defined in claim 1 in which said tube is entirely within the forward section of said tubular body. 7

5. The invention as defined in claim 1 in'which said other wedge means at the forward end of the tube is annular and interrupted at'circularly spaced intervals to form openings about the tube and through which gases maybe vented forwardly of the body from a space about the tube;

6; The invention as defined in claim 1 in which said tube has circularly spaced and circularly overlapping slots opening alternately at opposite ends of the tube to render the tube radially deformable throughout its length.

- References Cited iu the file of this patent I UNITED STATES PATENTS Keightleyj Jan. 13, 1959 

